The ideal nutrition changes over time — and can determine quality of life at each stage
It is widely agreed that following a balanced diet is one of the pillars of a healthy life. However, what we eat should evolve through the different stages of life, since nutritional needs change substantially between childhood, adulthood and old age.
A notable example comes from recent history. During the Second World War, the United Kingdom introduced a system of food rationing, allowing families a limited but balanced consumption of food. Sugar, for example, was restricted to about 227 grams per person per week — and children under two received no portion at all. When rationing ended in 1953, average sugar consumption doubled.
Decades later, a study published in 2025 revealed the impact of that difference. By analysing the medical records of 63,000 Britons born between 1951 and 1956, researchers concluded that those exposed to less sugar in the first 1,000 days of life had a significantly lower likelihood of developing cardiovascular disease, heart failure and stroke.
Childhood: building body and brain
According to Federica Amati, a nutritional scientist at Imperial College London, the first years of life are fundamental: “In childhood, food is literally building the body and the brain.” Beyond healthy calories, children need iron, iodine and a wide variety of vitamins to develop their immune system, brain and muscles.
Fruit, vegetables, wholegrains, pulses, quality fats (such as nuts and seeds) and as few ultra-processed foods as possible are essential. Calcium and vitamin D play a central role at this stage, as they are decisive for bone development and the future prevention of osteoporosis.
Adolescence and youth: consolidating healthy habits
Adolescence and the twenties represent another critical window. Although growth slows, it is a period of marked physical and mental demands. In addition to calcium and vitamin D, it is crucial to ensure an intake of iron (especially for those who menstruate), protein and B-complex vitamins.
Amati advises a mostly plant-based diet, rich in fruit, vegetables, wholegrains, pulses and seeds, with enough protein at every meal — plant-based if possible. As well as supporting the body, this dietary pattern can have a positive impact on mental health. Ultra-processed diets, according to studies, are associated with a higher incidence of depression and anxiety, whereas patterns such as the Mediterranean diet show protective effects.
That diet — rich in vegetables, olive oil, pulses and fish — also benefits fertility, in contrast to the Western pattern (high in saturated fat, meat and refined carbohydrates), which is associated with infertility in both women and men.
Middle age: preparing for future health
In middle age, it becomes essential to prepare the body for ageing. According to Elizabeth Williams, professor of human nutrition at the University of Sheffield, pre-menopausal women face accelerated loss of bone and muscle mass, as well as a higher risk of obesity, cardiovascular disease and type 2 diabetes, owing to falling oestrogen levels.
In this period, the key nutrients are calcium, vitamin D, quality protein and omega-3 fatty acids, found in fish such as salmon and mackerel. The latter reduce cardiovascular risks and have anti-inflammatory properties. The Mediterranean diet is once again singled out as ideal, promoting heart, bone, gut and even mental health.
A study of more than 100,000 Americans over 39 confirmed that diets rich in fruit, vegetables, wholegrains and unsaturated fats are strongly associated with healthy ageing — defined as living to 70 free of chronic disease and with good physical and cognitive function.
Old age: less energy, more nutrients
In old age, although calorie needs decrease, nutritional demands remain high. The priority again falls on calcium, vitamin D and protein — essential for preventing osteoporosis and sarcopenia (muscle loss).
Jane Murphy, a dietitian and co-lead of the Ageing and Dementia Research Centre at Bournemouth University, stresses that the combination of protein with good carbohydrates, healthy fats (such as olive oil, avocado, nuts and oily fish) and vitamins is crucial.
With age, the gut microbiome tends to lose diversity and balance, favouring the onset of diseases such as Alzheimer's, stroke and heart problems. However, people who reach 100 have a distinct microbiome, rich in beneficial bacteria such as Faecalibacterium prausnitzii. Promoting that balance depends, above all, on a diet rich in fibre and polyphenols — abundant in fruit and vegetables.
Researchers such as Mary Ni Lochlainn, of King's College London, point out that even the production of vitamin B12 and folic acid can be partly ensured by a healthy microbiome — compensating for common deficiencies at this stage.
In addition, supplements such as prebiotics (compounds that stimulate the growth of beneficial microorganisms) have been shown to improve cognition in older adults. Vitamin D, especially among elderly people in care homes, may also be beneficial.
